Halogenated unsaturated carbon compounds such as tetrafluoroethylene (TFE) are each widely used as a raw material of various types of chemical product such as a polymer material, and are extremely important industrial products for the industries. TFE is usually stored in a pressurized state. TFE is however highly unstable because TFE tends to polymerize, and special care needs to be taken for storage and transportation of TFE because TFE is explosive.
Various techniques have traditionally been developed to safely store and transport TFE. For example, Patent Document 1 describes methods for safely storing and safely transporting tetrafluoroethylene characterized in that tetrafluoroethylene is pressurized and dissolved into trifluoroethylene trichloride.
Patent Document 2 describes a method for stabilizing tetrafluoroethylene characterized in that perfluoroalkane having 1 to 5 carbon atom(s) is mixed with tetrafluoroethylene.
Patent Document 3 describes a method for transporting liquid tetrafluoroethylene in a container under pressure, and the method includes improvement including the fact that liquid carbon dioxide and the liquid tetrafluoroethylene are mixed with each other, and that carbon dioxide is present at an amount effective for preventing tetrafluoroethylene evaporated from the produced liquid mixture, from exploding at a temperature up to +25° C.
Patent Document 4 describes a shipping or storage container for long-term storage for tetrafluoroethylene, characterized in that the container includes tetrafluoroethylene in the form of a liquid mixture that includes tetrafluoroethylene and 35 to 65% by mol of hexafluoropropylene, and a gas space above the liquid mixture, and the gas space includes a mixture of vapors of tetrafluoroethylene and hexafluoropropylene from the liquid mixture.